This invention relates to an intra-aortic balloon pump which is inserted in an aorta percutaneously so as to assist the blood flow through a failing heart and to the body.
A percutaneous balloon pump includes a membrane and a catheter. The membrane is mounted on a proximal end of the catheter. The balloon pump is furled by wrapping the membrane around the catheter before insertion. Then, the balloon pump is inserted through a sheath into a femoral artery along a guide wire which is inserted in advance. The membrane ascends in a descending abdominal aorta toward the failing heart. After the membrane is properly positioned in the aorta, a sealing rubber cap which tightly surrounds the catheter is pressed to the sheath. The sealing rubber cap connects the catheter to the sheath in fluid tight manner. The sealing rubber cap closes an opening between the catheter and the sheath so as to prevent the blood from bleeding through the sheath. When pumping starts, the membrane immediately unwraps due to introduction of the pumping media and functions as an intra-aortic balloon. As shown in FIGS. 7 and 8, during the pumping, the membrane is inflated and deflated alternately so as to assist the blood flow through the failing heart and to the body.
While the wrapped membrane is inserted into the sheath, the membrane tends to be unwrapped and also tends to be deformed. FIG. 6 shows the membrane (5) which is inserted into a sheath (9). As described above, the membrane (5) has to be unwrapped when pumping starts. Therefore, the membrane (5) can be unwrapped and deformed very easily. Thus, even if the membrane (5) is inserted very carefully into the sheath (9), the membrane (5) often becomes wrinkled at an outside end (13) of the sheath (9). When the membrane (5) is inserted into the femoral artery, these wrinkles are gradually moved toward the catheter (4) and become larger and larger. In the worst situation, due to the large wrinkles, the balloon pump is difficult to insert into the sheath (9).